Frequently Asked Questions about Common Vectors

Antibiotic Usage

Transformations

Chloramphenicol - what concentration should I use?

Chloramphenicol concentration requirements in plates versus media is different. At the DGRC, we make a 34 mg/ml stock solution in 100% ethanol (store stock at -20).
Then for liquid cultures, add 2 microliters of stock to for every 1 ml of LB liquid culture (you can also get by with 1 microliter per ml if necessary). For plates, add 1 ml of stock chloramphenicol solution for every 1 Liter of media for plates.

Can I use electorporation on the Whatman discs?

Yes - Whatman has documented that this does work. We have not tried it at the DGRC but we have received the following information from a colleague who succesfully used electroporation: After rinsing with the TE for a few seconds he added electrocompetent XLI Blue cells (the lab's homemade) to the disc and incubated on ice for one minute. He then transferred the cells to a cuvette and electroporated. He plated the entire transformation on amp plates and obtained around 5 x 10^3 colonies.

Can I use glycogen precipitation?

We know of one person who tried a glycogen precipitation and centrifugation protocol as an alternative for recovering DNA from discs and did not have great success. We do not recommend trying this procedure as a means of recovering.

Citing the DGRC

When publishing experiments using materials obtained from the DGRC
please cite the Drosophila Genomics Resource Center, supported by NIH
grant 2P40OD010949, in the acknowledgments. Your cooperation helps us
when we need to renew our grant.